论文标题
用离域量子叠加测量重力时间扩张
Measuring gravitational time dilation with delocalized quantum superpositions
论文作者
论文摘要
原子钟可以用一般相对论预测的重力红移，而高度差异仅为1 cm。但是，所有现有的实验都涉及在不同位置进行两个独立时钟的比较，而不是在离域量子叠加中比较一个时钟。在这里，我们提出了一种采用组-II-type原子（例如SR或YB）的干涉法方案，该原子能够在两个不同高度的原子波包的相干叠加中测量重力时间扩张。与最近的其他提案相反，无需脉冲可以有效地衍射两个内部状态。取而代之的是，该方案依赖于非常简单的原子光学器件，在激光功率上需要相当温和的要求，可以实现高分量的效率。此外，通过使用同时充当惯性参考的RB干涉仪，减去振动噪声的影响。值得注意的是，最近受过委托的VLBAI设施位于汉诺威（Hannover），这是一个10米的原子喷泉，可以同时运行YB和RB原子，并实现多达2.8 s的自由进化时间，满足了成功实验实施的所有要求。
Atomic clocks can measure the gravitational redshift predicted by general relativity with great accuracy and for height differences as little as 1 cm. All existing experiments, however, involve the comparison of two independent clocks at different locations rather than a single clock in a delocalized quantum superposition. Here we present an interferometry scheme employing group-II-type atoms, such as Sr or Yb, capable of measuring the gravitational time dilation in a coherent superposition of atomic wave packets at two different heights. In contrast to other recent proposals, there is no need for pulses that can efficiently diffract both internal states. Instead, the scheme relies on very simple atom optics for which high-diffraction efficiencies can be achieved with rather mild requirements on laser power. Furthermore, the effects of vibration noise are subtracted by employing a simultaneous Rb interferometer that acts as an inertial reference. Remarkably, the recently commissioned VLBAI facility in Hannover, a 10-meter atomic fountain that can simultaneously operate Yb and Rb atoms and enables up to 2.8 s of free evolution time, meets all the requirements for a successful experimental implementation.
